Police had identified and were searching for a suspect Monday in Sunday’s double shooting that left a 17-year-old dead.

Marquis D. Costic, 22, with a last known address of 1614 W. Butler St., is wanted in connection with the slaying of Treyshawn Blakely, who was shot once in the head about 6 p.m. Sunday near Butler and Warren streets.

Costic is considered armed and dangerous, and anyone with information on his whereabouts or on the incident Sunday is asked to call Peoria police at 673-4521 or CrimeStoppers at 673-9000.

Police were called to the intersection about 6 p.m. after someone fired a .223-caliber semiautomatic rifle into a crowd that had gathered, striking Blakely, a second unidentified victim and houses in the area.

Blakely was transported to OSF Saint Francis Medical Center, where he was pronounced dead about 6:30 p.m. Preliminary autopsy results Monday indicated he died from a single gunshot wound to the head, according to Peoria County Coroner Johnna Ingersoll.

The second victim, whose name and age were not released, suffered injuries that police described as not being life-threatening.

“Bullets penetrated at least three homes. By God’s grace, no one was hit inside any of those homes,” police Chief Steve Settingsgaard said before the City Council meeting Monday night. “A number of people were standing outside, in the line of fire. Two people were hit. It surprised me we didn’t have more.”

Soon after the shooting Sunday night, police executed a search warrant at 1614 W. Butler St. and recovered an unspecified number of firearms, but not the weapon believed to have been used in the slaying.

Settingsgaard said drugs and gangs are involved in the shooting. Settingsgaard wouldn’t say which gang that was.

“There’s definite gang involvement in this case, and there is going to be a response from ‘Dont’ Shoot.’

“The shooting prior to that on Arago, we don’t have any gang connections. The shooting (Sunday) has very strong gang affiliations. We know which gang was involved.”

Dieuseul Brown, 25, 1522 S. Griswold St., has been charged with the fatal shooting of Kelsey Coleman at 1612 S. Arago St.

Costic has previous arrests for possessing a small amount of marijuana, domestic battery and failure to appear in court, according to Peoria County Jail records. He was last jailed in September 2010.

Tributes to Blakely on social media platforms Facebook and Twitter called him by his nickname, “Sunny,” and feature photos of a lanky teen. Family members contacted Monday by the Journal Star declined to comment.

According to multiple social media accounts and one witness who asked not to be named, Blakely was attending a barbecue at a home when a fight unrelated to the party broke out in the street.

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He joined the crowd to watch the fight when someone came out of a home with the rifle and fired into the group.

Funeral arrangements for Blakely had not yet been publicized by the end of the day Monday.

Matt Buedel can be reached at 686-3154 or mbuedel@pjstar.com. Follow him on Twitter @JournoBuedel.